1. Field of the Invention
The present invention generally relates to foundation systems utilized in construction and, more particularly, is concerned with a self-refrigerated foundation system for use in construction in permafrost zones.
2. Description of the Prior Art
Construction in permafrost zones throughout the world presents many unique difficulties not encountered in more temperate climates. During most of the year, the ground remains frozen solid providing solid support for structures. However, during the warmer summer months, the upper layer of soil may thaw. Also, if the structure is heated, heat radiating or conducting from the foundation of the structure can cause the upper layer of soil to thaw at any time of the year. When the ground thaws, the foundation loses the stability provided by frozen permafrost. This can cause the foundation to sink into the ground, often unevenly, resulting in substantial structural damage.
Various foundation systems are used to overcome the difficulties encountered in permafrost zones. One foundation system incorporates pilings that are placed deep into the ground. Installing pilings requires specialized equipment for boring piling holes and is therefore particularly expensive and time-consuming. Another foundation system utilizes an insulated pad beneath the structure. Insulated pads present two major drawbacks. A substantial amount of material must be hauled to the building site in order to construct the insulated pad, particularly if the structure is fairly large, and an insulated pad primarily addresses the problem of thawing due to radiated heat but ignores thawing that can occur during the warmer summer months. A third foundation system commonly employed is the refrigerated foundation system. Such foundation systems are designed to remove heat from the ground surrounding the foundation, thereby keeping the ground from thawing. Refrigerated foundation systems do not require the boring of deep holes and overcome both the problems of thawing due to heat radiated from the building and thawing during warmer summer months. However, prior known refrigerated foundations rely on active mechanical refrigeration units and are therefore expensive to construct, and because they require the input of energy to drive the active refrigeration units, they are fairly expensive to operate.
Consequently, a need still exists for a foundation system for use in construction in permafrost zones throughout the world that overcomes the problems of thawing during the warmer summer months and thawing due to radiated heat, is relatively inexpensive and simple to construct, and costs very little to operate.